Facebook’s role during the 2016 presidential election has come under extraordinary scrutiny in recent weeks. Most notably, attention has swirled around a Kremlin-backed troll farm’s purchase of $100,000 worth of ads on the platform during the election cycle. This came on the heels of controversies over the proliferation of "fake news" during the campaign.

But our research shows another, less discussed aspect of Facebook’s political influence was far more consequential in terms of the election outcome. The entirely routine use of Facebook by Trump’s campaign and others — a major part of the $1.1 billion of paid digital advertising during the cycle — is likely to have had far greater reach than Russian bots and fake news sites. And beyond this reach, our research reveals that firms such as Facebook, Google, and Twitter now play a much more active role in electoral politics than has been widely acknowledged.

Those companies had staff working hand in hand with Trump campaign digital staffers, according to Gary Coby, the director of advertising at the RNC and director of digital advertising and fundraising for Trump’s general election campaign. “I required that if people wanted to work with us, they needed to send bodies to us in Texas and put people on the ground because Hillary had this giant machine, well-built out with digital operations, and we're just a few guys and a big Twitter account,” he told us.

“Google, Twitter, and Facebook, we had people who were down there constantly and constantly working with us, helping us solve our problems in relation to how we're using the platforms,” he said. “If we're coming up with new ideas, bringing them into the fold to come up with ideas of how their platform could help us achieve our goals."

In light of Mark Zuckerberg’s recent announcement that Facebook will require disclosure and transparency around who creates and purchases political ads, it is worth considering the transparency of the behind-the-scenes work that enables the use of Facebook, Google, and Twitter to influence voters.

During and since the election, we formally interviewed dozens of staffers working on all the major 2016 campaigns, along with representatives of the big tech companies, to understand how campaigns use these platforms to reach the electorate. All of them echoed Coby’s comments that Google, Facebook, and Twitter play active roles in electoral politics.

For example, these firms offer an extensive array of campaign services — including advising campaigns on everything from the content of ads and other communications to the specific groups they might benefit most from targeting, and how best to reach them. Consider the fact that all three of these firms have dedicated partisan teams that work with campaigns. Staffers work with campaigns to guide advertising buys, boost engagement around online ads, and shepherd the use of their platforms.

One reason these firms have invested in working with campaigns is for a slice of the political ad sales market. The 2016 election alone was a $2 billion enterprise.

Technology firms and campaigns are both incentivized to work together — digital ads deliver revenue for technology companies based on engagement. This means that these firms get paid more based on higher performing ads: More click-throughs equal more revenue. For campaigns, more clicks mean greater reach and potential impact.

It’s not just the ad revenue alone that these firms are after. Presidential campaigns garner massive, worldwide attention. As such they serve as important vehicles for marketing these platforms and new tools they offer. Even more, we found that technology firms want to create relationships with campaigns to further their long-term lobbying efforts. Successful candidates become legislators, governors, and even presidents, with influence over the regulations, or lack thereof, that will apply to these firms.

Not all campaigns use Facebook, Twitter, and Google in the same way. Hillary Clinton built a large in-house staff to execute digital media on the campaign, but with a lean staff, the Trump team likely benefited more from the help provided by the tech companies. The expertise these firms provided to the campaign’s general-election San Antonio office was particularly important, and days after the election, Trump's digital director said Facebook played a "critical role" in its success.

You could consider the help provided by tech companies as a form of subsidy to the campaigns. These subsidies of expertise are mutually beneficial: The platforms get ad revenues and build relationships with campaigns and their candidates, while campaigns optimize their advertising and extend the reach of their messaging.

Ali-Jae Henke, the current head of industry, elections at Google, described the company’s routine work with campaigns during the cycle: “They say ‘like look, we really want to get attention and we want to reach as many people as possible and these are kind of the areas politically where we might have challenges or the different types of voting blocs we need to reach’ … and so then I am able to in that advisory capacity be like, ‘well this is what moms look like online, this is how we find them...’”

This work is of major importance, because even the most well-funded political campaigns are always strapped for time and resources, given the monumental task they have of contacting, motivating, and persuading the electorate. By enhancing the ability of institutional political actors to connect with citizens and make politics meaningful in an era of fragmented audiences and attention, we believe Google, Facebook, and Twitter are playing a significant role in the democratic process.

There is a troubling lack of transparency that clouds this role. Given the scope and scale of the paid uses of platforms such as Facebook by campaigns, the effects likely dwarf those of fake news or illegitimate advertising buys. This, of course, is speculation, because we will never know for certain how much impact these things had. That is why the basic lack of transparency and disclosure surrounding digital political advertising is so concerning, and Mark Zuckerberg’s recent announcement was a step in the right direction.

Google and Twitter should join Facebook in its effort around transparency and disclosure, and make the paid content posted on their platforms public so citizens, journalists, and academics can evaluate these messages. Government regulation around transparency is ideal. However, former chairperson Ann Ravel stated that the Federal Election Commission is “dysfunctional” and “deadlocked.” In the interim, these firms should work together to set standards for political advertising disclosure and open paid communications up to public scrutiny.

Daniel Kreiss is Associate Professor in the School of Media and Journalism at the University of North Carolina at Chapel Hill. His research explores the impact of technological change on the public sphere and political practice.

Shannon McGregor is an Assistant Professor in the Department of Communication at The University of Utah. Her research interests center on political communication, social media, gender, and public opinion.